This simple Manhattan salt house is artfully shaped... well, like a giant granule of salt.

The famous facade of Grand Central Terminal hides a regulation tennis court—and it's not the first one.

A replica of a 7th-century church hides in plain sight in the middle of the concrete jungle.

The former home of the reclusive "Weird Wendels" who dominated New York real estate a century before Donald Trump.

Manhattan's deadly West Side railroad, which killed hundreds of New Yorkers, is remembered by this simple plaque.

The rough and tumble president's childhood home displays the shirt he was once shot in and the speech that saved him.

This graffiti-covered bridge is the quintessential vision of a place for disillusioned youth to escape the complexities of burgeoning adulthood.

A Roman-inspired temple once controlled half of San Francisco's waters.

An alley covered with 20 years of bubble gum.

An eccentric home stands out in an otherwise average neighborhood with mosaics, mini topiaries, and kinetic sculpture.

A tree grown from astronaut seeds which were exposed to cosmic rays.

This massive redwood tree has a hole in the base big enough to drive through.

Abandoned bridge hidden deep in the San Gabriel Mountains.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Quite simply the largest tree in the world (by volume).

20,000 pieces in a Frank Gehry-designed building.

A tribute to the artist and activist who created the rainbow pride flag.

San Francisco’s century-old Christmas Tree.

A colorful, century-old cemetery of the Yaqui Indian Tribe hidden amid the suburban sprawl of Tempe, Arizona.

Where beautiful signs live on forever.

Recorded as the first person buried in Arlington Cemetery.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

This woodland architectural installation acts as a camera obscura for the heavens.

In the 19th century, this canal provided power to mills, machine shops, and other businesses in the area.